Embodiments of the present invention relate in general to data synchronization, and in particular to techniques for efficiently synchronizing data object instances between applications/processes.
Data synchronization refers to the process of keeping multiple copies of a dataset in coherence with each other. Data synchronization techniques are commonly used in a variety of different computing scenarios that require consistency between redundant/replicated data stores, such as multi-level cache architectures, distributed filesystems, high-availability database clusters, and the like.
In the field of computer networking, data synchronization techniques can be used to facilitate non-stop routing (NSR). Generally speaking, NSR enables a network router to gracefully handle the failure of an active management processor (active MP) within the router by failing over to a standby management processor (standby MP), without disrupting routing protocol interactions with other routers and without dropping any packets (known as hitless failover). NSR also allows for software upgrades to be performed on an active MP in the same hitless fashion.
To implement NSR, a router typically maintains data structures in a memory accessible by a standby MP that replicate data structures (e.g., routing table, neighbor database, etc.) used by a process running on an active MP in carrying out routing functions. Thus, if the active MP fails, the standby MP can automatically access the information it needs (via the replicated data structures) to take over routing functions in a seamless manner. As part of this implementation, data synchronization techniques are needed to ensure that the respective data accessible by the active and standby MPs remain in sync with each other. For example, while the active MP is available, the process running on the active MP can receive messages from other routers (e.g., link state advertisements, etc.) that require changes to its routing information. These changes need to be replicated in a consistent manner to the standby MP so that the standby has the most up-to-date routing data (in case of a subsequent failure in the active MP).
Unfortunately, existing data synchronization techniques have a number of limitations that limit their usefulness in this (and other similar) contexts. Merely by way of example, existing data synchronization techniques generally require creating an intermediate copy of the data to be synchronized in the memory accessible by the active MP, thereby consuming memory resources and decreasing performance. As another example, existing data synchronization techniques cannot easily support synchronization of different types of data objects (as may be needed for supporting NSR with respect to different routing protocols).